Metal arch.



n. GRAY.

METAL ARCH.

lication filed Jan. 2, 1902 Patented may 27, I902.

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(No Model.)

No. 7Ul,034. Patented May 27, I902. R. GRAY.

METAL ARCH.

(Application filed Jan. 2. 1902.}

3 Sheets-Sheet 3.

(No Model.)

UNiTnn STATES PATENT OFFICE.

RICHARD GRAY, OF BLOOMINGTON, ILLINOIS.

METAL ARCH.

SPECIFICATION formingpart of Letters Patent No. 701,034, dated May 27,1902; Application filed January 2, 1902. Serial No. 88,248. (No model.)

To ctZZ whom, it may concern:

Be it known that I, RICHARD GRAY, a citizen of the United States,residing at Bloomington, in the county of McLean and State of Illinois,have invented a new and useful Improvement in Metal Arches, of which thefollowing is a specification.

My invention relates to metal arches having adjustably-connected platesor voussoirs.

It particularly relates to the construction shown and described inLetters Patent of the United States No. 587,392, granted to me August 3,1897. o

The object of my invention is to increase the strength, reduce the cost,and simplify the construction of the metal arch.

To this end my invention consists of reducing the number of pieces and abetter distribution of materials to meet the varying stresses indifferent parts of the arch.

In my before-mentioned invention it is con templated to use cast-ironexclusively, whereas in this invention I'employ bands of wrou ghtiron orsteel.

That my invention may be more clearly understood the followingwell-known facts and principles are mentioned.

The least number of straight pieces of which it is possible to constructan arch is three, and the least number of joints is four. (See Figure 13in the drawings.) This is regarded as theprimaryarch.Archescomprisingagreater number of pieces may be treated as extensionsof the simple arch involving the same principles. In the case of theprimary or simple arch an eccentric load tends to a change of shape, asindicated by dotted lines in Fig. 13, producing bending moments ofopposite kinds at different joints. It is plain that the kind of momentat any joint depends upon the location of the load with respect to thejoint, and that therefore a moving load may produce both positive andnegative moments at all the joints; also, that the turning or rotationat all the joints must be simultaneous, and hence if ties or otherdevices are used to prevent turning the rotative force is opposed by thecombined resistance of allthe ties. The strength and rigidity of thearch will then be greater when all the joints are designed to resistrotation in both directions.

I n the masonry arch the rotative force is neutralized by fixing thedepth of the voussoirs, so that the line of resistance does not traverseoutside the body of the arch. Now it is well known that in the masonryarch if the line of resistance passes outside the body of the archfailure results by rotation and that the determination of the amplitudeof the traverse of the line of resistance for moving loads is verydifficult. It is evidently better, then, to construct the arch so thatthe joints will resist rotation.

An arch-bridge, especially beneath a railroad-track, is subject toshocks and Vibrations which any brittle material is ill adapted towithstand, and no piece composing a bridge should be liable to be shakenloose from its fastenings.

With reference to the foregoing facts this invention has been wroughtout, which I will now describe.

In the drawings, Fig. 1 is a perspective view of the metal work of myimproved arch. Fig. 2, partly in elevation and partly in section, showstwo joints and the connections. Fig. 3 is a plan or downward projectionfrom Fig. 2. Fig. 4: is a perspective view of an archplate. Fig. 5 is atransverse vertical section through the hinge at the joint. Fig. 6 is alongitudinal vertical section through the hinge on the dotted linethrough Fig. 5. Fig. 7 is a front elevation of the hinge. Fig. Sis aperspective view of the foundation-piece. Fig. 9 is an elevation of theend of an arch, showing the intrados in perspective. Fig. 10 is a sideelevation of the same. Fig. 11 is an elevation of two joints and theirconnections. Fig. 12 isa modified arch-plate in perspective. Fig. 13 hasbeen explained.

In the several figures, A A, 850., are the voussoirs of which the archis composed.

B B, &c., are the foundation-pieces.

a a, &c., are transverse flanges upon plate A, having projections f f,&c., or notches, as shown in Fig. 12.

Z) I), 850., are transverse flanges upon piece B.

c c, &c.,are small flanges at the ends, d d &c., small flanges near theedges, and h a small rib central, upon plate A. The plate A has upon oneedge a bead 7c, and upon the other edge a curvature m, adapted to engageand cover the bead 7c of an adjoining plate. The coverm has anenlargement n upon its upper surface opposite one end of the flange a.(See Fig.4.) The other end of flange a has a circular opening above thebead k. (See Fig. 12.) When two plates are put together, this openingadmits the passage of the cover on loosely and the enlargement atsnugly. The combination of the bead k and the undercut end of the flangea with the cover m and the enlargement n constitute a hinged connectionbetween the plates. The projections ff, &c., are notched in both edgesto receive the bands.

W W, 820., are flexible bands, which engage the projections ff, &c.

O O, &c., are small mortises or holes of any desired form throughflanges c c, placed opposite, so as to register when the plates are inproper position end to end. Bolts, pins, or keys are placed in the holes0 O, the, to hold the abutting plates evenly.

The flanges b b of piece B are notched upon their outer edges to receivethe wire bands, acting as anchors for these bands. The foundation-pieceB upon one side of the arch has. upon its upper edge the bead 7c and anopening beneath the end of flange b, the same as one edge of plate A,and upon the other side of the arch the foundation-piece has the cover mand enlargement n, the same as upon the other edge of plate A, so thatthe archplates form the same kind of hinge connection with thebase-pieces as they do with each other upon both sides of the arch.Plate B also has a base-flange which rests upon the foundation. Theplate B being cast integrally, the anchor-flange b is firmly attached tothe body of the plate and to the base-flange. The bands W W, 850., arepreferably composed of small steel Wire, the number of strands beingregulated by the amount of stress.

I prefer to erect the arch as follows: A wooden center is constructedfor a single arch-ring of any desired dimensions. I then connect theplates together, adjusting them to the curve of the support. I thenapply the wire bands, which I prefer to weave upon the projections asfollows: The end of the wire is fastened to a projection, preferably tothe anchor-flange b. It is passed to the next projection above, woundonce around this projection in the notches, thence to the nextprojection and wound once around in the notches, and so on over the archto the opposite anchor-flange, through the notch,

'thence returning, passing the wire around each projection insuccession, and continuing over the arch in alternate direction untilthe band is given the desired number of strands. If the wire iscontinuously wound in the same direction, there will be no crossingbetween the projections, which is preferable. It is plain, however, thatthe weaving may be such as to vary the number of strands in parts of thearch.

different parts of the band to meet" the requirements of differentstresses in different I maintain a moderate tension in the wire duringthe winding. After the band is woven it is twisted at each intervalbetween the projections by means of 'a lever inserted within the band,(see Fig. 2,) whereby any desired tension is obtained. This twistingalso effectually prevents the slipping of the projections within thebands.

I prefer to remove the lovers; but,if desired, they can be placed so asto prevent untwisting and allowed to remain. Succeeding rings areerected on either side of the first ring and joined together by the endconnections before mentioned.

The construction shown in Figs. 9 to 12, inclusive, is in all respectsthe same as above described, excepting the flanges a, which are notchedin the upper edges instead. of being cut away so as to leave theprojections ff, &c., and the short bands 8 s, &c., in these notchesinstead of the continuous bands W W, &c., over the entire arch. It isobvious that the bands W W, &c., and the ties s s, 850., can be made offlexible rods instead of wire. After the metal arch is erectedI apply acovering of concrete over the entire arch, as shown upon the left sideof Fig. 9.

Attention is now called to the following: The bands are applied withequal facility to the projections or flanges whatever may be theinclination of the plates to each other, (see Fig. 11,) therebyafiording the convenience without the complication and extra material ofadjustable couplings.

The bands are not liable to be broken or loosened by vibrations orshocks, are exceedingly simple and strong, and so elastic as to easilymeet the requirements of temperature strains in the arch. The tensiondue to negative moments is resisted by the bands or ties, while thecompression is resisted by the concrete. The hinged joint resists bothtension and compression, whence the combination fulfils the conditionsof greatest strength before mentioned.

I claim as new and useful as follows:

1. An arch made up of metallic plates adj ustably connected with eachother and bound together with flexible metallic bands.

2. An arch made up of metallic plates, adj ustably connected at theirinner faces, and

bound together with twisted metallic bands at or near their outer faces.

3. The hinge connection between the plates of a metal arch at theiredges comprising the bead 7c; the undercut end of flange a; and thecover m with the enlargement n upon its upper surface; substantially asdescribed.

4. A metal plate, adapted to join other metal plates in an arch, so asto form an adjustable connection with them, and having transverseflanges with projections or notches adapted to receive and retainflexible bands.

5. In an arch made up of metallic plates,

having transverse flanges; a twisted metallic ed to receive and retainthe ends of flexible 1o tie between the ends of said flanges, for themetallic bands, in combination with flexible purpose specified. metallicbands.

6. A band, comprising two or more strands In Witness whereof I havehereunto set my 5 of flexible metal applied to the voussoirs of I handin the presence of two witnesses.

a metal arch, and means for twisting said] RICHARD GRAY. strandstogether. I Witnesses:

7. As a part of a metal arch a foundation- JAMES GRAY,

picce,havin g anchors attached thereto adapt-' JOHN GRAY.

